Blower



Dec. 19, 1967 H. BANDLOW 3,358,911

BLOWER 2 Sheets-Sheet l Filed Sept. 7 17, 1965 INUENTOK FpEDP/(K H. BflNOAom/ W. LL24, AM AM AT TORN EV$ Dec. 19, 1967 H. BANDLOW BLOWER 2 Sheets-Sheet 2 Filed Sept. 17, 1965 INUENT'OE United States Patent s,3ss,911 BLOWER Frederick H. Bandlow, Theresa, Wis., assignor to Broan Mfg. (10., Inc., Hartford, Wis., a corporation of Wisconsin Filed Sept. 17, 1965, Ser. No. 488,225 7 Claims. (Cl. 230-114) ABSTRACT OF THE DISCLOSURE This disclosure relates to a cooking hood blower having spring pressed damper plates swung by a handle between blower port opening and closing positions. The dampers are on the inlet side of the air impeller so that the fiow of air through the ports tends to press the damper plates against the panels in which the ports are formed.

This invention relate to a blower. As illustrated in the present application, the blower has features which particularly adapt it for incorporation in a barbecue or similar cooking hood.

The blower of the present invention is a further development of the one disclosed in my copending United States patent application Ser. No. 352,809, filed Mar. 18, 1964, now United States Patent 3,279,681.

The characteristic feature of the present invention is the pair of spring pressed damper plates and the actuating mechanism by which these plates are swung between port opening and port closing position. The damper plates are advantageously disposed at the inlet side of the air impeller. Accordingly, the flow of air through the ports tends to press the damper plates against the panels through which the ports are formed, thus to reduce rattling and to produce a good seal between the dampers and the ports. Each damper is also provided with a biasing spring which maintains added pressure holding the damper tightly against the panel through which the port is formed. This pressure insures a good seal and also produces sufficient friction to hold the dampers in any position to which they are adjusted, without need for any additional detent mechanism.

An important advantage of disposing the damper plates at the intake side of the air impeller is that the dampers then intervene between the blower motor and the room space about the blower, thus to damp motor noise.

The invention further resides in the pecific actuating linkages and the interconnected swing lever and pintle for the respective dampers and by which both damper plates are concurrently moved under the force of a single control arm.

Other objects, features and advantages of the invention will appear from the following disclosure in which:

FIG. 1 is a perspective view of a blower embodying the present invention.

FIG. 2 is a vertical cross section taken through the blower of FIG. 1, along the line 2-2 of FIG. 4.

FIG. 3 is an end view of the blower of FIG. 2, an end filter being broken away to expose interior details.

FIG. 4 is a cross section taken along the line 44 of FIG. 2.

FIG. 5 is a fragmentary cross section taken along the line 55 of FIG. 4.

FIG. 6 is a fragmentary cross section taken along the line 6-6 of FIG. 3.

Although the disclosure hereof is detailed and exact to enable those skilled in the art to practice the invention, the physical embodiments herein disclosed merely exemplify the invention which may be embodied in other specific structure. The scope of the inventon is defined in the claims appended hereto.

Like the blower shown in my copending application aforesaid, the blower 10 of the present invention is adapted to be mounted in a hood over a barbecue grill or top burners of a range. Commercial embodiments of the present invention have a somewhat smaller capacity than those shown in my copending applicationf0r example, 350 c.f.m., although the invention is not limited to any particular unit size. The hood into which the blower fits is provided with an installation frame 11 to which the top wall 12 of the blower 10 is attached by the bolts 13. The edge margins of the top of the blower are typically positioned against the margins of an opening through the bottom of a soffit 14, as illustrated in FIGS. 2 and 4.

The blower 10 internally comprises laterally spaced parallel panels 15 which define walls between which the air impeller 16 is mounted. The air impeller 16 desirably comprises a single motor 17 having dual centrifugal or squirrel cage fans 18 at the respective ends of the motor armature shaft 19. The respective housing panel 15 are provided with port openings 21 which are axially aligned with each other and with the respective eyes 20 of the fan cages 18.

As shown in FIG. 4, air drawn into the cages 18 is expelled through the scroll housings 22 and out of the room space through the duct 23.

Motor 17 is a constant speed motor controlled by the off-on switch 24 shown in FIGS. 4 and 5. Switch 24 is actuated by the movement of bracing channel 25 on the swing arm structure for the damper plates 26.

Damper plates 26 are mounted to slide across the respective panels 15 to an end from port opening and closing position respecting the ports 21 therein. The dampers 26 are mounted on the respective ends of a cross pintle 27 which spans from one panel 15 to the other, and has ends projecting beyond each panel through panel openings provided for this purpose. Accordingly, the dampers 26 oscillate about the axis of pintle 27.

Radially spaced from pintle 27 is a cross swing arm 28 which spans also between the spaced panels 15 and has its ends projecting through arcuate slots 31 in said panels 15. The ends of cross swing arm 28 have a greater projection beyond the panels 15 than does pintle 27. The ends of the arm 28 are also threaded to receive adjusting nuts 32 by which the tension on leaf springs 33 can readily be adjusted. Leaf springs 33 are respectively anchored at corresponding ends by rivets 34 or the like to the damper plates 26 near their free swinging ends. The other corresponding ends of the leaf springs 33 have holes 35 confined under spring pressure about the projecting ends of the pintle 27. Intermediate their ends, the leaf springs 33 have oversized holes 36 about the projecting ends of the cross arm 28.

The leaf springs 33 are bowed outwardly to react between nuts 32 and the damper 26 to press the damper against the panel 15. Adjustment of the position of the nut 32 on the threaded ends of the arm 28 will increase or decrease the tension of the leaf springs 33. The leaf springs bias the damper plates 26 against the panels 15 to yieldingly hold the damper plates in any position to which they are adjusted by reason of the friction between the plates and the panels. This pressure provides a good seal between the damper plates 26 and the damper plate seat which consists of the marginal area of the panels 15 about the ports 21. Accordingly, wind pressure, etc. will not produce any rattling in the dampers and there is no need to provide any extraneous detent mechanism to hold the dampers in set position.

Inasmuch as the respective damper plates 26 are on the respective outsides of the panels 15, the reaction of the interconnecting cross arm 28 to the pressure of one spring 33 will be communicated to the other spring 33. Accordingly, the pressure of the pair of springs 33 is opposed, thus to provide a balanced pressure of the respective dampers on the panels 15. In this manner, damper pressure is equalized so that each damper provides substantially the same resistance to adjustment.

The dampers are adjusted by means of the lever arm or handle 37 which is attached by pin 41 to the shaft 42. Handle 37 is swingable in and out with respect to the front wall 38 of the blower housing on the pin 41, as shown by arrows 29 in FIG. 4. It is also swingable transversely in the direction of arrows 39 in FIG. 1, to turn shaft 42.

Shaft 42 is provided with a crank arm 43 connected to the hooked end 44 of the link 45 which has its opposite hooked end 46 engaged with crank 47. Crank 47 constitutes a strut which interconnects pintle 27 with cross swing arm 28, at corresponding points intermediate their length. The pintle 27, cross arm 28 and the crank arm 47 are rigidly braced for concurrent movement about the axis of pintle 27 by the channel 25. Accordingly, the respective parts just named swing as a unit about the axis of the pintle 27 to smoothly and uniformly communicate the pressure of the control lever 37 to both of the damper plates 26 and to cause sliding movement of the dampers 26 across the panels without binding, etc.

As before noted, the channel 25 also functions as an actuator for switch 24 for the blower motor 17. Switch 24 will de-energize the motor 17 when the dampers are in closed position. As soon as the dampers swing to any open position thereof, switch 24 will be relieved of the pressure of the channel 25, thus to energize the motor 17 and cause air flow through the blower.

The amount of air flow will be determined entirely by the position of the dampers, and the load on the motor will vary according to the position of the dampers. When the dampers are almost closed and little air is flowing through the air impeller, the load on the motor will be relatively small, and light current will be drawn. When the dampers are wide open with large quantities of air flowing therethrough, the load on the motor and the current drawn thereby will be correspondingly increased. Accordingly, the motor load and power demand will be determined entirely by the adjusted position of the dampers. Accordingly, there is no need for providing any other load or speed control mechanism. for the motor.

The control lever 37 is alse provided with a switch actuating plate 48. Actuator plate 48 is confined for swinging movement in the direction of arrows 39 within the arcuate channel guide 51. By pushing the handle 37 inwardly toward the wall 38, switch actuator plate 48 will actuate off-on switch 52 for the electric lamp 53. Switch 52 is of the off-on variety so that every time the switch 52 is actuated, the lamp will either be turned on or off and will remain so until the switch is again actuated. Shaft 42 also carries a bracket 30 for spring 56 which biases lever 37 away from contact with switch 52.

The described damper construction in which the dampers are on the inlet sides of the air impeller 16 advantageously interposes the damper plates 26 between the air impeller 16 and the room space about the blower. Accordingly, noise generated in the air impeller will tend to be damped by the dampers. Moreover, the air flow into the housing will further tend to bias the damper plates 26 toward the walls 15 to assist the springs 33.

The blower 10 further comprises inlet air plenum chambers 54 which are closed by the removable filter screens 55. Filter screens 55 have a much greater area than the area of ports 21, thus to provide substantial areas for filtering the incoming air and increase the filtering capacity thereof.

In the disclosed embodiment, the leaf springs 33 are augmented by additional leaf springs 57 which bear on the projecting ends of pintle 27. Auxiliary springs 57 tend to concentrate spring pressure on the free swinging ends of the damper plates 26.

I claim:

1. A blower comprising a housing having laterally spaced walls respectively with axially aligned air inlet ports, an air impeller between the walls to draw air into the housing through said ports, a slide damper for each port, a cross pintle projecting between said walls and connected to each damper, a cross swing arm offset radially from the pintle axis and connected to the dampers, crank means for totating the cross swing arm about the axis of the pintle to swing the dampers with respect to the ports, and springs reacting between the cross swing arm and the dampers to bias the dampers against the said spaced walls.

2. The blower of claim 1 in which the respective dampers are outside the said walls, said walls having slots through which the ends of the cross arm project and along which said ends travel during swinging movement of the dampers, said springs being outside the housing and reacting between the dampers and the projecting ends of the cross swing arm.

3. The blower of claim 2 in which said springs comprise leaves bowed outwardly away from the dampers, and adjustable couplers on the ends of the cross swing arm in pressure engagement with the bowed part of the leaf springs to impose their bias on the dampers.

4. The blower of claim 1 in further combination with a brace interconnecting the pintle and cross swing arm along the major portion of their length.

5. The blower of claim 4 in which the crank means comprises a strut interconnecting the cross swing arm and pintle and disposed intermediate the ends thereof.

6. A blower comprising a housing having laterally spaced walls respectively with axially aligned air inlet ports, an air impeller between the walls to draw air into the housing through said ports, a slide damper for each port, a cross pintle projecting between said walls and connected to each damper, a cross swing arm offset radially from the pintle axis and connected to the dampers, crank means for rotating the cross swing arm about the axis of the pintle to swing the dampers with respect to the ports, said dampers being outside the said walls to be biased by air fiow through said ports against said walls.

7. In a blower having an air impeller and a housing panel with a port for air flow induced by the impeller, the improvement comprising:

a swing plate damper,

a handle and linkages coupling the handle to the swing plate,

a pintle olfset laterally from the port about which the damper swings with respect to the port to open and close the port,

and a spring biasing the damper against said panel.

References Cited UNITED STATES PATENTS 544,069 8/1895 Pearson 251-179 1,797,293 3/ 1931 McIlvaine 230-114 2,013,816 9/1935 West 2301 14 2,850,228 9/ 1958 Rowley 230--114 HENRY F. RADUAZO, Primary Examiner.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,358,911 December 19, 1967 Frederick H. Bandlow ified that error appears in the above numbered pat- It is hereby cert said Letters Patent should read as ent requiring correction and that the corrected below.

Column 3, line {17, for "alse" read also column 4, line 17, for "totating" read rotating line 23, for "cross arm" read cross swing arm Signed and sealed this 18th day of March 1969.

(SEAL) Attest:

EDWARD J. BRENNER Edward M. Fletcher, Jr.

Commissioner of Patents Attesting Officer 

1. A BLOWER COMPRISING A HOUSING HAVING LATERALLY SPACED WALLS RESPECTIVELY WITH AXIALLY ALIGNED AIR INLET PORTS, AN AIR IMPELLER BETWEEN THE WALLS TO DRAW AIR INTO THE HOUSING THROUGH SAID PORTS, A SLIDE DAMPER FOR EACH PORT, A CROSS PINTLE PROJECTING BETWEEN SAID WALLS AND CONNECTED TO EACH DAMPER, A CROSS SWING ARM OFFSET RADIALLY FROM THE PINTLE AXIS AND CONNECTED TO THE DAMPERS, CRANK MEANS FOR TOTATING THE CROSS SWING ARM ABOUT THE AXIS OF THE PINTLE TO SWING THE DAMPERS WITH RESPECT TO THE PORTS, AND SPRINGS REACTING BETWEEN THE CROSS SWING ARM AND THE DAMPERS TO BIAS THE DAMPERS THE SAID SPACED WALLS. 